Greater Scaup
(Aythya marila)


Picture of bird
© Ralph Hocken
For additional photos and vocalizations, visit Dendroica. (Link opens in a new window.)

Two Scaup species occur in Canada, the Greater Scaup and the Lesser Scaup. These two closely related species are nearly identical in appearance, which can cause difficulties in distinguishing them. The population status of Scaup in North America became a conservation concern due to apparent declines from historic high levels observed in the late 1970s. Their populations have not yet fully recovered, and research to understand the cause of the decline is ongoing. Greater Scaup are the least abundant of the two species and are the only diving duck with a circumpolar breeding distribution. It is widely distributed across Arctic and Subarctic regions where it mainly nests in coastal tundra habitats. The information below regarding the population estimate and population status is for the two species combined. This species has been identified as a priority for conservation and/or stewardship in one or more Bird Conservation Region Strategies in Canada.


Main designations for the species
DesignationStatusDateSubspecies, population
IUCN (Global)Least concern2018 
Partners in Flight (North America)Common birds in steep decline2017 
Wild Species (Canada)Secure2015 
Bird Conservation Region StrategyPriority Species2013 

Population status

Geographic area or populationPopulation change relative to ~1970ReliabilityStatus in relation to goal
CanadaModerate DecreaseLowData Deficient

Distribution maps


Migration strategy, occurrence

Short-distance migrant

Responsibility for conservation

Geographic areaResponsibility based on % of global population

General nesting period in Canada

Nesting period starts between late May and early June and ends between early August and mid-August, depending on the region. Before or after this period, the probability of an active nest is lower.

Conservation and management

As it is very difficult to differentiate between Greater Scaup and Lesser Scaup during aerial surveys and most ground-based surveys, species-specific population estimates and population trends cannot be obtained. Because Lesser Scaup are a dominant component of the combined population, changes in population status of the less abundant Greater Scaup may be undetectable. Research is ongoing to understand why Scaup have declined during the drought years in the 1980s (similarly to other ducks), but were slow to recover when habitat conditions improved subsequently (Austin et al. 2000, Anteau et al. 2014). The harvest of Scaup has declined considerably in Canada over the long-term.


Bird conservation region strategies

Environment and Climate Change Canada and partners have developed Bird Conservation Region Strategies in each of Canada’s Bird Conservation Regions (BCRs). In these strategies, selected species are identified as priorities for one or more of the following reasons:

  • conservation concerns (i.e., species vulnerable due to population size, distribution, population trend, abundance, or threats)
  • stewardship responsibilities (i.e., species that typify the regional avifauna or have a large proportion of their range or population in the sub-region)
  • management concerns (i.e., species that require ongoing management because of their socio-economic importance as game species, or because of their impacts on other species or habitats)
  • other concerns (i.e., species deemed a priority by regional experts for other reasons than those listed above or because they are listed as species at risk or concern at the provincial level)

Select any of the sub-regions below to view the BCR strategy for additional details.

BCRs, marine biogeographic units, and sub-regions in which the species is listed as a priority
RegionSub-region and priority type
Arctic Plains and MountainsArctic Plains and Mountains, sub-region and priority type: Quebec -- Other
Boreal Hardwood TransitionBoreal Hardwood Transition, sub-region and priority type: Ontario and Manitoba -- Conservation
Great BasinGreat Basin, sub-region and priority type: Pacific and Yukon -- Other
Lower Great Lakes/St. Lawrence PlainLower Great Lakes/St. Lawrence Plain, sub-region and priority type: Quebec -- Other
Northern Pacific RainforestNorthern Pacific Rainforest, sub-region and priority type: Pacific and Yukon -- Other
Taiga Shield and Hudson PlainsTaiga Shield and Hudson Plains, sub-region and priority type: Prairie and Northern -- Other